If you mean to say your fourth answer is correct I beg to differ. !/fee/ aborts for "fee" anywhere in the string instead of only at the start like the OP wanted

UPDATE:

If you mean to say your third answer is correct I beg to differ. It expects a '/' after "fee". While this is always the case in the examples it is not what the OP said (although there is a chance that the OP misstated the problem)